U.S. patent number 10,913,021 [Application Number 15/285,534] was granted by the patent office on 2021-02-09 for water purification device.
This patent grant is currently assigned to The Johns Hopkins University. The grantee listed for this patent is The Johns Hopkins University. Invention is credited to Brad M. Ward, Zhiyong Xia.
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United States Patent |
10,913,021 |
Xia , et al. |
February 9, 2021 |
Water purification device
Abstract
A water purification device includes a heavy metal removal layer
configured to remove heavy metal ions and perfluorinated compounds
from contaminated water. The water purification device may further
include a biological species removal layer configured to remove
biological species from the contaminated water and a support layer
configured to provide support for the water purification
device.
Inventors: |
Xia; Zhiyong (Rockville,
MD), Ward; Brad M. (Frederick, MD) |
Applicant: |
Name |
City |
State |
Country |
Type |
The Johns Hopkins University |
Baltimore |
MD |
US |
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Assignee: |
The Johns Hopkins University
(Baltimore, MD)
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Family
ID: |
1000005349494 |
Appl.
No.: |
15/285,534 |
Filed: |
October 5, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170203244 A1 |
Jul 20, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62279853 |
Jan 18, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D
39/1623 (20130101); B01D 39/2041 (20130101); C02F
1/001 (20130101); C02F 2305/08 (20130101); C02F
2101/20 (20130101); C02F 2303/04 (20130101); C02F
2201/008 (20130101); B01D 2239/0442 (20130101); C02F
2101/36 (20130101); B01D 2239/0258 (20130101); B01D
2239/025 (20130101); C02F 2303/20 (20130101) |
Current International
Class: |
B01D
39/16 (20060101); B01D 39/20 (20060101); C02F
1/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Yang et al., Alumina nanofibers grafted with functional groups,
Oct. 2009, Water Research vol. 44, pp. 741-750 (Year: 2009). cited
by examiner .
Sereshti et al., Electrospun PET nanofibers as a new absorbent for
micro-solid phase extraction of chromium (VI) in environmental
water sample, Oct. 2015, pp. 89195-89203 (Year: 2015). cited by
examiner .
Min et al., Functionalized chitosan electrospun nanofiber for
effective removal of trace arsenate from water, Aug. 2016, pp. 1-12
(Year: 2016). cited by examiner .
Hejazi et al., Electrospun nanofibrous composite membranes of
chitosan/PVA-PAN, Nov. 2014, pp. 1959-1966 (Year: 2014). cited by
examiner .
Cummings et al., Recommendation on Perfluorinated compound
treatment options for drinking water, Jun. 2015, pp. 1-12 (Year:
2015). cited by examiner .
Botes et al., The potential of nanofibers and nanobiocides in water
purification, Jan. 2010, Critical Reviews in Microbiobiology, vol.
36, pp. 68-81 (Year: 2010). cited by examiner .
Du et al. Adsorption behavior and mechanism of perfluorinated
compounds on various adsorbents, Apr. 2014, Journal of Hazardous
Materials, vol. 274, pp. 443-454, (Year: 2014). cited by examiner
.
CDC, A Guide to Drinking Water Treatment Technologies for Household
use, Mar. 2014, pp. 1-3 (Year: 2014). cited by examiner.
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Primary Examiner: Orme; Patrick
Attorney, Agent or Firm: Hayward; Noah J.
Government Interests
STATEMENT OF GOVERNMENTAL INTEREST
This invention was made with Government support under contract
number N00024-13-D-6400 awarded by the Naval Sea Systems Command
(NAVSEA). The Government has certain rights in the invention.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to and the benefit of U.S.
Provisional Application Ser. No. 62/279,853 filed on Jan. 18, 2016,
the entire contents of which are hereby incorporated herein by
reference.
Claims
That which is claimed is:
1. A water purification device comprising: a heavy metal removal
layer configured to filter heavy metal ions and perfluorinated
compounds from contaminated water, the heavy metal removal layer
comprising a nanofiber web having a functional group bonded
thereto, wherein the functional group is configured to attract and
bond the heavy metal ions, and wherein the nanofiber web comprises
a plurality of nanofiber pores, each of the plurality of nanofiber
pores having a nanofiber pore size from 100 nanometers to 50,000
nanometers; a biological species removal layer configured to filter
biological species from the contaminated water; and a support layer
configured to provide support for the water purification device and
comprising a microfiber web, the microfiber web comprising a
plurality of microfiber pores, wherein each of the plurality of
microfiber pores has a microfiber pore size of 2 nanometers to
7,000 nanometers.
2. The water purification device according to claim 1, wherein the
support layer is disposed between the heavy metal removal layer and
the biological species removal layer.
3. The water purification device according to claim 1, wherein the
functional group is a thiol or a mercaptan functional group.
4. The water purification device according to claim 1, wherein the
nanofiber web comprises at least polyethylene terephthalate.
5. The water purification device according to claim 1, wherein the
biological species removal layer comprises a plurality of
positively-charged nano-whiskers.
6. The water purification device according to claim 5, wherein the
positively-charged nano-whiskers are aluminum oxide hydroxide
nano-whiskers.
7. The water purification device according to claim 6, wherein the
aluminum oxide hydroxide nano-whiskers are in boehmite form.
8. The water purification device according to claim 1, wherein the
microfiber web comprises deep groove microfibers.
9. The water purification device according to claim 8, wherein the
deep groove microfibers are micron-sized deep groove
microfibers.
10. The water purification device according to claim 1, wherein the
water purification device further comprises an anti-fouling layer
configured to prevent clogging of the water purification
device.
11. The water purification device according to claim 10, wherein
the anti-fouling layer is located on a first end of the water
purification device such that the contaminated water flows first
through the anti-fouling layer.
12. The water purification device according to claim 10, wherein
the anti-fouling layer comprises a nanofiber web with nanoparticles
embedded therein, wherein the nanoparticles are configured to
prevent adhesion of particles from the contaminated water onto the
first end of the water purification device.
13. The water purification device according to claim 12, wherein
the nanoparticles are chitosan nanoparticles.
14. The water purification device according to claim 12, wherein
the nanofiber web is comprised of at least polyvinyl alcohol.
15. The water purification device according to claim 1, wherein the
water purification device further comprises an enhanced biological
species removal layer configured to filter biological species not
filtered via the biological species removal layer, wherein the
biological species removal layer is positioned in the water
purification device such that the contaminated water flows first
through the biological species removal layer before flowing through
the enhanced biological species layer.
16. The water purification device according to claim 1, wherein the
water purification device further comprises a perfluorinated
compound removal layer configured to filter heavy metal ions and
perfluorinated compounds not filtered via the heavy metal removal
layer, wherein the heavy metal removal layer is positioned in the
water purification device such that the contaminated water flows
first through the heavy metal removal layer before flowing through
the perfluorinated compound removal layer.
17. The water purification device according to claim 1, wherein the
nanofiber pore size is from 500 nanometers to about 1000
nanometers.
Description
TECHNICAL FIELD
Example embodiments relate generally to water purification devices,
and more particularly to water purification devices that can filter
heavy metals, perfluorinated compounds and biological species.
BACKGROUND
A number of contaminants contribute to the pollution of water
sources. These contaminants include a) biological species, such as
disease causing bacteria; b) toxic heavy metal ions, such as lead,
mercury, arsenic, cadmium, and copper; and c) organic contaminants,
such as perfluorinated compounds ("PFCs") that include
perfluorooctane sulfonate ("PFOS") and perfluorooctanoic acid
("PFOA"). Biological species tend to cause acute illness, and toxic
heavy metal ions tend to accumulate in complex organs such as the
liver, heart, and brain to cause serious illness from long-term
exposure. The presence of PFOS and PFOA in the human blood is also
particularly concerning as they have been found in greater than 90%
of the U.S. population and may lead to cancer, liver damage, or
birth defects. Moreover, due to the chemical nature of PFOS and
PFOA, they are extremely difficult to remove from water. Existing
techniques used to purify water include reverse osmosis ("RO"),
activated carbon, micro-/nano-filtration membranes, ion exchange
resins, iodine, bleach, ultra-violet lights, and mixed oxidants
such as sodium hypochlorite. Unfortunately these existing
technologies are only effective in removing one type of contaminant
(i.e., they are configured to efficiently remove only one of
biological species, heavy metals, or PFCS). For example, for the
removal of heavy metal ions, common used techniques include RO,
filtration, distillation, and nano-metal oxides. These techniques,
however, suffer from low removal efficiency and poor selectivity
issues. For the removal of PFCs, common used techniques include
activated carbon, membrane filtration, ion exchange, and oxidation.
All four methods, however, suffer from low removal rate, high cost,
and poor selectivity. For the removal of biological species,
chemical disinfectants (such as iodine, bleach and sodium
hypochlorite) may be used, but they may exert odor to the
water.
BRIEF SUMMARY OF SOME EXAMPLES
In one example embodiment, a water purification device is provided.
The water purification device may include a heavy metal removal
layer configured to remove heavy metal ions from contaminated
water. The water purification device may further include a
biological species removal layer configured to remove biological
species from the contaminated water and a support layer configured
to provide support for the water purification device.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
Having thus described the vehicle in general terms, reference will
now be made to the accompanying drawings, which are not necessarily
drawn to scale, and wherein:
FIG. 1 illustrates an exploded view of the water purification
device according to an example embodiment;
FIG. 2 illustrates a graph demonstrating the introduction of the
thiol functional group onto the surface of the nanofiber web of the
heavy metal removal layer according to an example embodiment;
FIG. 3 illustrates reaction chemistry used to quantify the
concentration of the thiol functional group on the nanofiber web of
the heavy metal removal layer according to an example
embodiment;
FIG. 4 illustrates a graph demonstrating the level of the thiol
functional group on the nanofiber web of the heavy metal removal
layer according to an example embodiment;
FIGS. 5-7 illustrate charts demonstrating the percentage of heavy
metal ion removal using the nanofiber web of the heavy metal
removal layer according to an example embodiment;
FIG. 8 illustrates a chart demonstrating the percentage of PFC
removal using the nanofiber web of the heavy metal removal layer
according to an example embodiment;
FIG. 9 illustrates an exploded view of the water purification
device according to a further example embodiment;
FIG. 10 illustrates an exploded view of the water purification
device according to a further example embodiment;
FIG. 11 illustrates an exploded view of the water purification
device according to a further example embodiment; and
FIG. 12 illustrates an exploded view of the water purification
device according to a further example embodiment.
DETAILED DESCRIPTION
Some example embodiments now will be described more fully
hereinafter with reference to the accompanying drawings, in which
some, but not all example embodiments are shown. Indeed, the
examples described and pictured herein should not be construed as
being limiting as to the scope, applicability, or configuration of
the present disclosure. Rather, these example embodiments are
provided so that this disclosure will satisfy applicable legal
requirements. Like reference numerals refer to like elements
throughout.
Example embodiments described herein relate to a water purification
device that is configured to remove heavy metal ions and biological
species from contaminated water. Moreover, in some cases, the water
purification device may also remove PFCs from the contaminated
water. The water may come from a variety of sources including
rivers, ponds, swamps, wells, or the like. As described above, in
the past in order to filter one of heavy metal ions, biological
species, and PFCS from contaminated water, different treatment
technologies have been needed (e.g., for heavy metals: RO,
filtration, distillation, and nano-metal oxides; for biological
species: chemical disinfectants (such as iodine, bleach, and sodium
hypochlorite); and for PFCs: activated carbon, membrane filtration,
ion exchange, and oxidation). These known technologies for removing
each of heavy metal ions, biological species, and PFCs are highly
incompatible. In other words, because these technologies are
incompatible (i.e., having different and competing chemistry), one
filtration device has been unable to filter out heavy metal ions,
biological species, and PFCs from contaminated water. Accordingly,
example embodiments described herein relate to a water purification
device that may perform multiple functions, such as removing each
of heavy metal ions, PFCs, and biological species from contaminated
water.
Therefore, the water purification device described herein may have
a high selectivity toward heavy metal ions and PFCs while
maintaining a high surface charge to filter out biological species.
Moreover, the water purification device may be cost-effective as
the water purification device may require less energy or pressure
to ensure high filtration efficiency. Additionally, the water
purification device may have a high specific surface area while
maintaining high filtration efficiency at high porosity levels.
Furthermore, since the device does not employ free disinfecting
chemicals, the filtered water will not have any unpleasant odors or
tastes. Moreover, the water purification device described herein
may be incorporated into portable water purification systems,
vehicle-based water filtration systems, or any other filtration
system known in the art.
The term "nonwoven", as used herein, may comprise a web having a
structure of individual fibers or threads which are interlaid, but
not in an identifiable manner as in a knitted or woven fabric.
Non-woven webs have been formed by many processes such as, for
example, meltblowing processes, spunbonding processes,
hydroentangling, air-laid, and bonded carded web processes.
The term "pore", as used herein, may comprise any structure formed
by the nonwoven fiber fabric assembly having a maximal pore size.
The random arrangement of the nonwoven fibers may create irregular
pore structures. Thus, the pores may have irregular shapes and
inconsistent sizes generally. As such, the pore size should be
understood to correlate to the size of the smallest object that
would be retained by or prevented from passing through the
pore.
The term "embedded", as used herein, may generally refer to the
placement and capture of nanoparticles within nanofiber web either
secured within the nanofiber web or on the surface of the nanofiber
web.
In one aspect, a water purification device suitable for a wide
variety of end-uses is provided. Water purification devices,
according to some example embodiments herein, may include many
features including the ability to remove both biological species
and heavy metal ions, and in some cases PFCs, from contaminated
water while being configured to be incorporated into existing water
purification systems. In general, the water purification device may
include at least a layer configured to remove biological species, a
layer configured to remove heavy metal ions, and a layer configured
to provide support to the water purification device.
FIG. 1 illustrates an exploded view of the water purification
device according to an example embodiment. As shown in FIG. 1, the
water purification device 10 may include a plurality of layers. In
some cases, the water purification device 10 may include a heavy
metal removal layer 20, a support layer 30, and a biological
species removal layer 40. According to one example embodiment, the
support layer 30 may be disposed between the biological species
removal layer 40 and the heavy metal removal layer 20. In some
cases, the support layer 30 may be sandwiched between (i.e.,
located directly between, without other layers disposed between,
the biological species removal layer 40 and the heavy metal removal
layer 20). However, in other example embodiments, the support layer
30 may be located on an end of the water purification device 10 and
either of the biological species removal layer 40 or the heavy
metal removal layer 20 may be sandwiched between the support layer
30 and the other of the biological species removal layer 40 or the
heavy metal removal layer 20. Moreover, in some cases, the heavy
metal removal layer 20 may located on or proximate a first end of
the water purification device 10 such that the contaminated water
is first filtered through the heavy metal removal layer 20.
However, according to further example embodiments, the contaminated
water may be first filtered through the biological species layer 40
and then through the heavy metal removal layer 20.
The heavy metal removal layer 20 of the water purification device
10 may be configured to remove heavy metal ions from the
contaminated water. Moreover, in accordance with other example
embodiments, the heavy metal removal layer 20 may be configured to
remove both heavy metal ions and PFCs. In some cases, the heavy
metal removal layer 20 may be a nonwoven having a functional group
bonded thereto. The nonwoven of the heavy metal removal layer 20,
therefore, may include a randomly oriented or aligned collection of
nanofibers. In some embodiments, for example, the nonwoven of the
heavy metal removal layer 20 may be a nanofiber web in the form of
a thick and tangled mass defined by an open texture or porosity.
According to certain embodiments, for instance, the nanofiber web
of the heavy metal removal layer 20 may be formed using an
electrospinning production process. In such embodiments, the
morphologies of the nanofiber web of the heavy metal removal layer
20 may be arbitrarily controlled using different electrospinning
settings. In other embodiments, for example, the nanofiber web of
the heavy metal removal layer 20 may be formed using additive
manufacturing means.
In accordance with an example embodiment, the nanofiber web of the
heavy metal removal layer 20 may include polymer-based fibers.
Accordingly, the nanofiber web of the heavy metal removal layer 20
may include only one polymer or a blend of polymers. The polymer or
blend of polymers may be a synthetic polymer such as poly(lactic
acid) ("PLA"), poly(L-lactic acid) ("PLLA"),
poly(lactic-co-glycolic acid) ("PLGA"), polycaprolactone ("PCL"),
poly(ethylene oxide) ("PEO"), poly(ethylene terephthalate) ("PET"),
poly(vinyl alcohol) ("PVA"), or any combination thereof. In certain
embodiments, for example, the nanofiber web may include only PET
nanofibers.
Further, the nanofiber web of the heavy metal removal layer 20 may
include a fiber diameter from about 5 nanometers ("nm") to about
2000 nanometers ("nm"). In further embodiments, for example, the
nanofiber web of the heavy metal removal layer 20 may include a
fiber diameter from about 100 nm to about 1000 nm. In other
embodiments, for instance, the nanofiber web of the heavy metal
removal layer 20 may include a fiber diameter from about 200 nm to
about 750 nm. In some embodiments, for example, the nanofiber web
of the heavy metal removal layer 20 may include a fiber diameter of
about 500 nm. As such, in certain embodiments, the nanofiber web of
the heavy metal removal layer 20 may include a fiber diameter from
at least about any of the following: 5, 50, 100, 200, 300, 400, and
500 nm and/or at most about 2000, 1000, 750, 700, 600, and 500 nm
(e.g., about 100-700 nm, about 400-600 nm, etc.).
Moreover the nanofiber web of the heavy metal removal layer 20 may
include a plurality of pores (i.e., a pore structure) configured
for efficient interaction between heavy metal ions and/or PFCs and
the nanofiber web for best removal rate. Accordingly, the pore size
and the shape, as well as how the pores are interconnected, may at
least partially determine the types of heavy metal ions and/or PFCs
that may be removed from the contaminated water. In some cases, the
plurality of pores may have a relatively small pore size thus
resulting in a high specific surface area. Accordingly, the
nanofiber web of the heavy metal removal layer 20 may include a
pore size from about 100 nm to about 50,000 nm. In further
embodiments, for example, the nanofiber web of the heavy metal
removal layer 20 may include a pore size from about 200 nm to about
6000 nm. In other embodiments, for instance, the nanofiber web of
the heavy metal removal layer 20 may include a pore size from about
300 nm to about 5000 nm. In certain embodiments, for example, the
nanofiber web of the heavy metal removal layer 20 may include a
pore size from about 500 nm to about 1000 nm. As such, in certain
embodiments, the nanofiber web of the heavy metal removal layer 20
may include a pore size from at least about any of the following:
100, 200, 300, 400, and 500 nm and/or at most about 50,000, 10,000,
7000, 6000, 5000, 3000, 2000, 1000, and 500 nm (e.g., about 100
nm-1000 nm, about 500 nm-1000 nm, etc.).
While the pore size of the nanofiber web of the heavy metal removal
layer 20 may contribute to the removal of at least some of the
heavy metal ions and/or PFCs from the contaminated water, in some
cases, the nanofiber web of the heavy metal removal layer 20 may
also include a functional group attached thereto to further
increase the removal efficiency of the heavy metal ions and/or PFCs
from the contaminated water. Thus, the nanofiber web of the heavy
metal removal layer 20 may maintain a high specific surface area
while being able to filter out a high percentage of the heavy metal
ions and/or PFCs from the contaminated water. Because the heavy
metal removal layer 20 may have a high specific surface area, less
pressure may be needed to enable the removal efficiency of the
contaminants from the water. Thereby, any system that the water
purification device 10 may be utilized in will require less energy
or pressure thereby reducing the costs associated with purifying
the contaminated water.
The functional group bonded to the nanofiber web of the heavy metal
removal layer 20 may be any functional group capable of attracting
and binding heavy metals ions thus increasing the removal
efficiency of the heavy metal removal layer 20. In some cases, as
shown in FIG. 1, the functional group may be a thiol or a mercaptan
(R-SH) functional group. Moreover, in some example embodiments, the
thiol functional group may be introduced under different solvent
conditions (e.g., acid, base, neutral, ethanol/HCl, H.sub.2O/HCl,
NH4OH, or toluene). In some cases, the thiol functional group may
be introduced with the use of mercaptan silane. The mercaptan
silane may be any type of mercaptan silane such as
3-mercaptopropyltrimethoxysilane ("MPTMS"),
11-mercaptoundecyltrimethoxysilane, S-(octanoyl)
mercaptopropyltriethoxysilane,
3-mercaptopropylmethyldimethoxysilane,
(mercaptomethyl)methyldiethoxysilane, and
3-mercaptopropylmethyldimethoxysilane.
In accordance with an example embodiment herein, the thiol level
present on the nanofiber web of the heavy metal removal layer 20
may be from about 5 to 100 .mu.mole/mg of nanofiber web. In further
embodiments, for example, the thiol level present on the nanofiber
web of the heavy metal removal layer 20 may be from about 5 to 50
.mu.mole/mg of nanofiber web. In other example embodiments, for
example, the thiol level present on the nanofiber web of the heavy
metal removal layer 20 may be from about 5 to 20 .mu.mole/mg of
nanofiber web. As such, in certain embodiments, the thiol level
present on the nanofiber web of the heavy metal removal layer 20
may be from at least about any of the following: 5, 8, 10, 12, 15,
and 20 .mu.mole/mg of nanofiber web and/or at most about any of the
following: 100, 80, 75, 60, 50, 35, 25, and 20 .mu.mole/mg of
nanofiber web.
As further shown in FIG. 1, the water purification device 10 may
also include a biological species removal layer 40 that is
configured to remove biological species from contaminated water. In
such embodiments, for instance, the biological species removal
layer 40 may be a nonwoven. In some cases, the biological species
removal layer 40 may include a plurality of nano-whiskers formed
into a nonwoven web or mat. In accordance with some example
embodiments, the nano-whiskers may be bonded to a microglass
non-woven scaffold in order to form a nonwoven. The nano-whiskers
may be formed according to any process known in the art.
Accordingly, the nonwoven of the biological species removal layer
40 may include a fiber diameter from about 10 nm to about 2000 nm.
In further embodiments, for example, the nonwoven of the biological
species removal layer 40 may include a fiber diameter from about
100 nm to about 1000 nm. In other embodiments, for instance, the
nonwoven of the biological species removal layer 40 may include a
fiber diameter from about 250 nm to about 750 nm. In some
embodiments, for example, the nonwoven of the biological species
removal layer 40 may include a fiber diameter of about 500 nm. As
such, in certain embodiments, the nonwoven of the biological
species removal layer 40 may include a fiber diameter from at least
about any of the following: 80, 100, 250, 300, 400, and 500 nm
and/or at most about 2000, 1000, 750, 700, 600, and 500 nm (e.g.,
about 100-700 nm, about 400-600 nm, etc.).
In accordance with an example embodiment, the nano-whiskers of the
nonwoven of the biological species removal layer 40 may be formed
from any suitable material capable of imparting a positive charge
on a surface of the biological species removal layer 40. In some
cases, for example, the nano-whiskers may be aluminum oxide
hydroxide (AlOOH) nano-whiskers. In accordance with further example
embodiments, the nano-whiskers may be AlOOH in the boehmite form.
The biological species removal layer 40, therefore, may rely at
least partially on the positive charge of the nano-whiskers when
contacted with water in order to remove the contaminants rather
than, for example, solely on the pore size of the nonwoven of the
biological species removal layer 40. In other words, biological
contaminants or species may be mainly negatively charged under most
conditions. Accordingly, the biological species removal layer 40,
via the electroadhesion process, may utilize the positively-charged
nano-whiskers of the biological species removal layer 40 in order
to filter negatively-charged biological species from the
contaminated water. In some cases, however, the biological species
layer 40 may rely on a combination of both the positive charge of
the nano-whiskers and the pore size of the nonwoven of the
biological species removal layer 40 in order to filter out
biological species from the contaminated water.
Accordingly, the nanofiber web of the biological species removal
layer 40 may include a plurality of pores (i.e., a pore structure)
configured to filter out at least some of the biological species.
Accordingly, the pore size may at least partially determine the
types of biological species that may be removed from the
contaminated water. In some cases, the plurality of pores may have
a relatively large pore size thus resulting in a high specific
surface area. Accordingly, the nonwoven of the biological species
removal layer 40 may include a pore size from about 100 nm to about
7000 nm. In further embodiments, for example, the nonwoven of the
biological species removal layer 40 may include a pore size from
about 200 nm to about 6000 nm. In other embodiments, for instance,
the nonwoven of the biological species removal layer 40 may include
a pore size from about 300 nm to about 5000 nm. In certain
embodiments, for example, the nonwoven of the biological species
removal layer 40 may include a pore size from about 500 nm to about
1000 nm. As such, in certain embodiments, the nonwoven of
biological species removal layer 40 may include a pore size from at
least about any of the following: 100, 200, 300, 400, and 500 nm
and/or at most about 7000, 6000, 5000, 3000, 1000, and 500 nm
(e.g., about 100 nm-1000 nm, about 500 nm-1000 nm, etc.).
As further shown in FIG. 1, the water purification device 10 may
also include a support layer 30 that is configured to provide
support and structure to the water purification device 10. In such
embodiments, for instance, the support layer 30 may be a nonwoven
that includes a randomly oriented or aligned collection of
microfibers. In some embodiments, for example, the microfiber web
of the support layer 30 may be in the form of a thick and tangled
mass defined by an open texture or porosity. According to some
example embodiments, the microfibers of the support layer 30 may be
deep groove microfibers to promote capillary action on the surface
of the support layer 30. In further example embodiments, the
microfibers of the support layer 30 may be micron-sized deep groove
microfibers.
In accordance with an example embodiment, the microfiber web of the
support layer 30 may include polymer-based fibers. Accordingly, the
microfiber web of the support layer 30 may include only one polymer
or a blend of polymers. The polymer or blend of polymers may be a
synthetic polymer such as poly(lactic acid) ("PLA"), poly(L-lactic
acid) ("PLLA"), poly(lactic-co-glycolic acid) ("PLGA"),
polycaprolactone ("PCL"), poly(ethylene oxide) ("PEO"),
poly(ethylene terephthalate) ("PET"), poly(vinyl alcohol) ("PVA"),
or any combination thereof. In other cases, the microfiber web of
the support layer 30 may include fibers formed from a combination
of a polymer and glass (e.g., fiberglass).
Furthermore, the microfiber web of the support layer 30 may include
a fiber diameter from about 0.5 .mu.m to about 200 .mu.m. In
further embodiments, for example, the microfiber web of the support
layer 30 may include a fiber diameter from about 0.5 .mu.m to about
100 .mu.m. In other embodiments, for instance, the microfiber web
of the support layer 30 may include a fiber diameter from about 0.5
.mu.m to about 50 .mu.m. In some embodiments, for example, the
microfiber web of the support layer 30 may include a fiber diameter
of about 10 .mu.m. As such, in certain embodiments, the microfiber
web of the support layer 30 may include a fiber diameter from at
least about any of the following: 0.5, 1, 2, 3, 4, 5, and 10 .mu.m
and/or at most about 200, 100, 50, 40, 30, 20, and 10 .mu.m (e.g.,
about 2 .mu.m-100 .mu.m, about 4 .mu.m-100 .mu.m, etc.).
Moreover, the microfiber web of the support layer 30 may include a
plurality of pores (i.e., a pore structure) configured to allow the
water to pass through and, in some cases, to filter out large
particulates in the water. In some cases, the plurality of pores
may have a relatively large pore size thus resulting in a high
specific surface area. Accordingly, the microfiber web of the
support layer 30 may include a pore size from about 2 nm to about
7000 nm. In further embodiments, for example the microfiber web of
the support layer 30 may include a pore size from about 50 nm to
about 6000 nm. In other embodiments, for instance, the microfiber
web of the support layer 30 may include a pore size from about 100
nm to about 5000 nm. In certain embodiments, for example, the
microfiber web of the support layer 30 may include a pore size from
about 500 nm to about 1000 nm. As such, in certain embodiments, the
microfiber web of the support layer 30 may include a pore size from
at least about any of the following: 2, 50, 100, 200, 300, 400, and
500 nm and/or at most about 7000, 6000, 5000, 3000, 1000, and 500
nm (e.g., about 100 nm-1000 nm, about 500 nm-1000 nm, etc.).
FIG. 2 illustrates a graph demonstrating the introduction of the
thiol functional group onto the surface of the nanofiber web of the
heavy metal removal layer 20. As shown in FIG. 2, an FTIR trace
graph shows the presence of the thiol functional group at 2250
cm.sup.-1 and several other characteristic absorption bands. Based
on the FTIR analysis demonstrated in the graph, the thiol
functional group has been introduced on to the surface of the
nanofiber web of the heavy metal removal layer 20.
FIG. 3 illustrates reaction chemistry used to quantify the
concentration of the thiol functional group on the nanofiber web of
the heavy metal removal layer 20. As shown in FIG. 3, the Ellman
reagent (5,5'-dithiobis-(2-nitrobenzoic acid ("DTBN")) is reacted
with thiol to result in 2-nitoro-5-thiobenzoic acid ("TNB").
Accordingly, the Ellman reagent may be used to quantify the thiol
concentration introduced on the surface of the nanofiber web of the
heavy metal removal layer 20.
FIG. 4 illustrates a graph demonstrating the level of the thiol
functional group on the nanofiber web of the heavy metal removal
layer 20. As shown in FIG. 4, a UV-Vis absorption spectrum
illustrates the level of the thiol functional group on the
nanofiber web of the heavy metal removal layer 20, where the thiol
has been treated under different conditions. It should be
understood that the peak at 412 nm may be used to quantify the
amount of the thiol functional group on the nanofiber web of the
heavy metal removal layer 20. Accordingly, in some cases,
thiol-ethanol (EtOH/HCl) may have approximately 0.4 absorbance.
Moreover, for example, thiol-toluene may have approximately 0.45
absorbance. Additionally, for example, thiol-water (H.sub.2O/HCl)
may have 0.75 absorbance.
FIGS. 5-7 illustrate charts demonstrating the percentage of heavy
metal ion removal using the nanofiber web of the heavy metal
removal layer 20. As shown in FIG. 5, water was contaminated with
only one heavy metal ion at a time, such as arsenic, cadmium, lead,
copper, and mercury. Moreover, three conditions were evaluated for
introducing the thiol functional group onto the nanofiber web of
the heavy metal removal layer 20: 1) toluene (neutral condition);
2) H2O/HCl (acid catalyzed); and 3) EtOH/HCl (acid catalyzed). The
heavy metal removal rate was calculated by comparing the heavy
metal concentration in the influent and the heavy metal ion
concentration in the effluent. It should be understood that a
higher removal value indicates a better heavy metal removal
rate.
As shown in FIG. 6, the water was contaminated with a combination
of heavy metal ions including arsenic, cadmium, lead, copper, and
mercury. The concentration of all the heavy metal ions in the water
is 100 ppb. It should be understood that all tests were performed
at a pH of 2.98, as a low pH may be needed for maintaining the
adequate solubility of mercury in the water. Moreover, the thiol
was treated with EtOH/HCl (acid catalyzed). As is demonstrated in
the results of FIG. 6, the addition of the thiol functional group
to the nanofiber web of the heavy metal removal layer 20 results in
increased efficiency when removing any of arsenic, cadmium, lead,
copper, or mercury from water.
As shown in FIG. 7, water was contaminated with mercury. Moreover
three conditions were evaluated for introducing the thiol
functional group onto the nanofiber web of the heavy metal removal
layer 20: 1) toluene (neutral condition); 2) H2O/HCl (none
catalyzed); and 3) EtOH/HCl (acid catalyzed). It should be
understood that all tests were performed at a pH of 0.5, as a low
pH may be needed for maintaining the adequate solubility of mercury
in the water. As demonstrated in FIG. 7, the addition of the thiol
functional group to the nanofiber web of the heavy metal removal
layer 20 results in increased efficiency when removing mercury from
the water. Moreover, even after repeated passes through the heavy
metal removal layer 20, the heavy metal removal layer 20 continues
to be effective at removing mercury from the water.
FIG. 8 illustrates a chart demonstrating the percentage of PFC
removal using the nanofiber web of the heavy metal removal layer
20. As shown in FIG. 8, water was contaminated with only one PFC at
a time, such as perfluorobutanesulfonic acid ("PFBS"),
perfluorohexane sulfonate ("PFHXS"), perfluoroheptanoate ("PFHp
A"), PFOS, PFOA, and perfluorononanoic acid ("PFNA"). Moreover, the
thiol functional group was introduced with the use of MPTMS. As is
demonstrated in the results of FIG. 8, the addition of the thiol
functional group to the nanofiber web of the heavy metal removal
layer 20 results in increased efficiency when removing any PFBS,
RFHXS, PFHp A, PFOA, PFOS, or PFNA.
FIG. 9 illustrates an exploded view of the water purification
device 10 according to a further example embodiment. As shown in
FIG. 9, in addition to including the heavy metal removal layer 20,
the biological species removal layer 40, and the support layer 30
as described above, the water purification device 10 may also
include a PFC removal layer 45. According to one example
embodiment, the PFC removal layer 45 may be disposed proximate the
heavy metal removal layer 20. In some cases, the PFC removal layer
45 may be disposed between the biological species removal layer 40
and the heavy metal removal layer 20. In other cases, the PFC
removal layer 45 may be sandwiched between (i.e., located directly
between, without other layers disposed between, the biological
species removal layer 40 and the heavy metal removal layer 20).
However, in other example embodiments, the PFC removal layer 45 may
located on or proximate a first end of the water purification
device 10 such that the contaminated water is first filtered
through the PFC removal layer 45. However, according to further
example embodiments, the contaminated water may be first filtered
through the heavy metal removal layer 20 and then through the PFC
removal layer 45.
The PFC removal layer 45 of the water purification device 10 may be
configured to remove PFCs and/or heavy metal ions from the
contaminated water. Accordingly, the PFC removal layer 45 may be
configured in substantially the same manner as the heavy metal
removal layer 20 described above. In some cases, when the water
purification device 10 includes both a heavy metal removal layer 20
and a PFC removal layer 45, the PFC removal layer 45 may be
configured to provide for the additional removal of heavy metal
ions or PFCs that were perhaps not removed by the heavy metal
removal layer 20. Accordingly, the PFC removal layer 45 may be
situated in the water purification device 10 such that the
contaminated water flows first through the heavy metal removal
layer 20. In accordance with other example embodiments, however,
the heavy metal removal layer 20 may be configured to remove only
the heavy metal ions, and the PFC removal layer 45 may be
configured to remove only PFCs.
FIG. 10 illustrates an exploded view of the water purification
device according to a further example embodiment. As shown in FIG.
10, in addition to including the heavy metal removal layer 20, the
biological species removal layer 40, and the support layer 30 as
described above, the water purification device 10 may also include
an anti-fouling layer 50. According to one example embodiment, the
anti-fouling layer 50 may be provided on an end of the water
purification device 10 such that the contaminated water flows first
through the anti-fouling layer 50. Accordingly, the anti-fouling
layer 50 may be proximate either of the heavy metal removal layer
20 or the biological species removal layer 40 such that the support
layer 30 is sandwiched between the biological species removal layer
40 and the support layer 30. However, in other example embodiments,
the support layer 30 may be located at an opposite end of the water
purification device 10 from the anti-fouling layer 50, and the
biological species removal layer 40 and the heavy metal removal
layer 20 may be sandwiched between the support layer 30 and the
anti-fouling layer 50.
The anti-fouling layer 50 may be configured to prevent fouling or
clogging of the water purification device 10 and may be a nonwoven
having nanoparticles embedded therein. The nonwoven of the
anti-fouling layer 50, therefore, may include a randomly oriented
or aligned collection of nanofibers. In some embodiments, for
example, the nanofiber web of the anti-fouling layer 50 may be in
the form of a thick and tangled mass defined by an open texture or
porosity. According to certain embodiments, for instance, the
nanofiber web of the anti-fouling layer 50 may be formed using an
electrospinning production process. In such embodiments, the
morphologies of the nanofiber web of the anti-fouling layer 50 may
be arbitrarily controlled using different electrospinning settings.
In other embodiments, for example, the nanofiber web of the
anti-fouling layer 50 may be formed using a solid state polymer
multilayer extrusion process.
In accordance with an example embodiment, the nanofiber web of the
anti-fouling layer 50 may include polymer-based fibers.
Accordingly, the nanofiber web of the anti-fouling layer 50 may
include only one polymer or a blend of polymers. The polymer or
blend of polymers may be a synthetic polymer such as poly(lactic
acid) ("PLA"), poly(L-lactic acid) ("PLLA"),
poly(lactic-co-glycolic acid) ("PLGA"), polycaprolactone ("PCL"),
poly(ethylene oxide) ("PEO"), poly(ethylene terephthalate) ("PET"),
poly(vinyl alcohol) ("PVA"), or any combination thereof. In certain
embodiments, for example, the nanofiber web of the anti-fouling
layer 50 may include PVA nanofibers.
Furthermore, the nanofiber web of the anti-fouling layer 50 may
include a fiber diameter from about 5 nm to about 1000 nm. In
further embodiments, for example, the nanofiber web of the
anti-fouling layer 50 may include a fiber diameter from about 20 nm
to about 700 nm. In other embodiments, for instance, the nanofiber
web of the anti-fouling layer 50 may include a fiber diameter from
about 100 nm to about 500 nm. In some embodiments, for example, the
nanofiber web of the anti-fouling layer 50 may include a fiber
diameter of about 100 nm. As such, in certain embodiments, the
nanofiber web of the anti-fouling layer 50 may include a fiber
diameter from at least about any of the following: 5, 10, 20, 50,
and 100 nm and/or at most about 1000, 800, 700, 600, 500, and 100
nm (e.g., about 50-500 nm, about 100-800 nm, etc.).
Moreover, the nanofiber web of the anti-fouling layer 50 may
include a plurality of pores (i.e., a pore structure) configured
such that the anti-fouling layer 50 has a high specific surface
area. Accordingly, the nanofiber web of the anti-fouling layer 50
may include a pore size from about 100 nm to about 7 .mu.m. In
further embodiments, for example, the nanofiber web of the
anti-fouling layer 50 may include a pore size from about 20 nm to
about 200 .mu.m. In other embodiments, for instance, the nanofiber
web of the anti-fouling layer 50 may include a pore size from about
100 nm to about 100 .mu.m. In certain embodiments, for example, the
nanofiber web of the anti-fouling layer 50 may include a pore size
from about 500 nm to about 50 .mu.m. As such, in certain
embodiments, the nanofiber web of the anti-fouling layer 50 may
include a pore size from at least about any of the following: 100,
200, 300, 400, and 500 nm and/or at most about 200, 100, 50, 3, and
1 .mu.m (e.g., about 100 nm-1 .mu.m, about 500 nm-1 .mu.m,
etc.).
In accordance with an example embodiment, the nanofiber web of the
anti-fouling layer 50 may have a plurality of nanoparticles adhered
onto a surface of the nanofiber web of the anti-fouling layer 50.
In some cases, the nanoparticles may be any type of nanoparticles
suitable for preventing the colonization of microbes on the surface
of the nanofiber web, or preventing the attaching of microbes, both
of which will decrease the tendency of the nanofiber surface from
forming biofilms, or fouling. Accordingly, in some cases, the
nanoparticles may be chitosan nanoparticles, silver nanoparticles,
or copper nanoparticles, or any combination thereof. According to
some example embodiments, the nanoparticles may cover 5% to 100% of
the surface area of the nanofiber web of the anti-fouling layer 50.
In other example embodiments, for example, the nanoparticles may
cover 5% to 75% of the surface area of the nanofiber web of the
anti-fouling layer 50. In other example embodiments, for example,
the nanoparticles may cover 5% to 50% of the surface area of the
nanofiber web of the anti-fouling layer 50. As such, in certain
embodiments, the nanoparticles may cover from at least about any of
the following: 5, 10, 20, 30, 40, or 50% of the surface area of the
nanofiber web of the anti-fouling layer 50 and/or at most about any
of the following: 100, 80, 75, 70, 60, or 50% of the surface area
of the nanofiber web of the anti-fouling layer 50.
Moreover, the nanoparticles may form a nano-sized pattern on the
surface of the nanofiber web of the anti-fouling layer 50 to
further prevent the adhesion of particles to the surface the
nanofiber web of the anti-fouling layer 50. The formation of these
nanostructure on the surface of layer 50 will trap micro-size air
bubbles which prevents the attachment of microbes in the water,
thus reducing the fouling of the water purification device 10.
FIG. 11 illustrates an exploded view of the water purification
device 10 according to a further example embodiment. As shown in
FIG. 11, in addition to including the heavy metal removal layer 20,
the biological species removal layer 40, the support layer 30, and
the anti-fouling layer 50 as described above, the water
purification device 10 may also include an enhanced biological
species removal layer 60. According to one example embodiment, the
structure of the water purification device 10 may be similar to
those described above (e.g., the anti-fouling layer 50 may be
provided on an end of the water purification device 10 such that
the contaminated water flows first through the anti-fouling layer
50, where the anti-fouling layer 50 may be proximate either of the
heavy metal removal layer 20 or the biological species removal
layer 40 such that the support layer 30 is sandwiched between the
biological species removal layer 40 and the heavy metal removal
layer 20). However, the enhanced biological species removal layer
60 may be provided in the water purification device 10 in a manner
such that the contaminated water flows first through the biological
species removal layer 40. For example, the enhanced biological
species removal layer 60 may be provided on an end of the water
purification device 10 opposite from the anti-fouling layer 50, or
in some cases, proximate the biological species layer 40, as long
as the contaminated water flows first through the biological
species removal layer 40.
The enhanced biological species removal layer 60 may be configured
to further provide for the additional removal of biological species
that were perhaps not removed by the biological species layer 40.
Moreover, the enhanced biological species removal layer 60 may be
in the form of a nonwoven layer. The nonwoven of enhanced
biological species removal layer 60, therefore, may include a
randomly oriented or aligned collection of nanofibers. In some
embodiments, for example, the nanofiber web of the enhanced
biological species removal layer 60 may be in the form of a thick
and tangled mass defined by an open texture or porosity. According
to certain embodiments, for instance, the nanofiber web of the
enhanced biological species removal layer 60 may be formed using an
electrospinning production process. In such embodiments, the
morphologies of the nanofiber web of the enhanced biological
species removal layer 60 may be arbitrarily controlled using
different electrospinning settings. In other embodiments, for
example, the nanofiber web of the enhanced biological species
removal layer 60 may be formed using a solid state polymer
multilayer extrusion process.
In accordance with an example embodiment, the nanofiber web of the
enhanced biological species removal layer 60 may include
polymer-based fibers. Accordingly, the nanofiber web of the
enhanced biological species removal layer 60 may include only one
polymer or a blend of polymers. The polymer or blend of polymers
may be a synthetic polymer such as poly(lactic acid) ("PLA"),
poly(L-lactic acid) ("PLLA"), poly(lactic-co-glycolic acid)
("PLGA"), polycaprolactone ("PCL"), poly(ethylene oxide) ("PEO"),
poly(ethylene terephthalate) ("PET"), poly(vinyl alcohol) ("PVA"),
or any combination thereof. In certain embodiments, for example,
the nanofiber web of the enhanced biological species removal layer
60 may include PET nanofibers.
Furthermore, the nanofiber web of the enhanced biological species
removal layer 60 may include a fiber diameter from about 10 nm to
about 100 .mu.m (i.e., 100,000 nm). In further embodiments, for
example, the nanofiber web of the enhanced biological species
removal layer 60 may include a fiber diameter from about 100 nm to
about 50 .mu.m (i.e., 50,000 nm). In other embodiments, for
instance, the nanofiber web of the enhanced biological species
removal layer 60 may include a fiber diameter from about 250 nm to
about 750 nm. In some embodiments, for example, the nanofiber web
of the enhanced biological species removal layer 60 may include a
fiber diameter of about 500 nm. As such, in certain embodiments,
the nanofiber web of the enhanced biological species removal layer
60 may include a fiber diameter from at least about any of the
following: 80, 100, 250, 300, 400, and 500 nm and/or at most about
100,000, 50,000, 10,000, 1,000, 750, 700, 600, and 500 nm (e.g.,
about 100-700 nm, about 400-600 nm, etc.).
Moreover, the nanofiber web of the enhanced biological species
removal layer 60 may include a plurality of pores (i.e., a pore
structure) configured to remove any biological species that was
perhaps not removed by the biological species removal layer 40.
Accordingly, the nanofiber web of the of the enhanced biological
species removal layer 60 may include a pore size that is configured
to filter those biological species that may be likely to have not
been removed by the biological species layer 40. Accordingly, the
nanofiber web of the of the enhanced biological species removal
layer 60 may include a pore size from about 10 nm to about 7 .mu.m.
In further embodiments, for example, the nanofiber web of the
enhanced biological species removal layer 60 may include a pore
size from about 100 nm to about 6 .mu.m. In other embodiments, for
instance, the nanofiber web of the enhanced biological species
removal layer 60 may include a pore size from about 300 nm to about
5 .mu.m. In certain embodiments, for example, the nanofiber web of
the enhanced biological species removal layer 60 may include a pore
size from about 500 nm to about 1 .mu.m. As such, in certain
embodiments, the nanofiber web of the enhanced biological species
removal layer 60 may include a pore size from at least about any of
the following: 100, 200, 300, 400, and 500 nm and/or at most about
7, 6, 5, 3, and 1 .mu.m (e.g., about 100 nm-1 .mu.m, about 500 nm-1
.mu.m, etc.).
FIG. 12 illustrates an exploded view of the water purification
device 10 according to a further example embodiment. As shown in
FIG. 12, in addition to including the heavy metal removal layer 20,
the biological species removal layer 40, the support layer 30, the
anti-fouling layer 50, and the enhanced biological species removal
layer 60 as described above, the water purification device 10 may
also include a second support layer 70. According to one example
embodiment, the structure of the water purification device 10 may
be similar to those described above (e.g., the anti-fouling layer
50 may be provided on an end of the water purification device 10
such that the contaminated water flows first through the
anti-fouling layer 50, where the anti-fouling layer 50 may be
proximate either of the heavy metal removal layer 20 or the
biological species removal layer 40 such that the support layer 30
is sandwiched between the biological species removal layer 40 and
the heavy metal removal layer 20). However, in cases where the
second support layer 70 is provided in the water purification
device 10, the second support layer 70 may be sandwiched between
the heavy metal removal layer 20 and the enhanced biological
species removal layer 60, as shown in FIG. 12. In other cases, for
example, the second support layer 70 may be provided on an opposite
end of the water purification device 10 from the anti-fouling layer
50.
The second support layer 70 may be configured to provide additional
support and structure to the water purification device 10. In such
embodiments, for instance, the second support layer 70 may be a
nonwoven that includes a randomly oriented or aligned collection of
microfibers. In some embodiments, the nonwoven second support layer
70 may include a randomly oriented or aligned collection of
microfibers. In some embodiments, for example, the microfiber web
of the second support layer 70 may be in the form of a thick and
tangled mass defined by an open texture or porosity.
In accordance with an example embodiment, the microfiber web of the
second support layer 70 may be formed in a similar manner as the
support layer 30. For example, the support layer 70 may include
polymer-based fibers or a combination of polymer and glass fibers.
Furthermore, the microfiber web of the second support layer 70 may
include a fiber diameter from about 0.5 .mu.m to about 200 .mu.m.
In further embodiments, for example, the microfiber web of the
second support layer 70 may include a fiber diameter from about 0.5
.mu.m to about 100 .mu.m. In other embodiments, for instance, the
microfiber web of the second support layer 70 may include a fiber
diameter from about 1 .mu.m to about 50 .mu.m. In some embodiments,
for example, the microfiber web of the second support layer 70 may
include a fiber diameter of about 5 .mu.m. As such, in certain
embodiments, the microfiber web of the second support layer 70 may
include a fiber diameter from at least about any of the following:
0.5, 1, 10, 20, 30, 40, and 50 .mu.m and/or at most about 200, 100,
80, 70, 60, and 50 .mu.m.
Moreover, the microfiber web of the second support layer 70 may
include a plurality of pores (i.e., a pore structure) configured
allow the water to pass through. In some cases, the plurality of
pores may have a relatively large pore size thus resulting in a
high specific surface area. The microfiber web of the second
support layer 70 may include a pore size from about 100 nm to about
200 .mu.m. In further embodiments, for example, the microfiber web
of the second support layer 70 may include a pore size from about
200 nm to about 100 .mu.m. In other embodiments, for instance, the
microfiber web of the second support layer 70 may include a pore
size from about 300 nm to about 10 .mu.m. In certain embodiments,
for example, the microfiber web of the second support layer 70 may
include a pore size from about 500 nm to about 1 .mu.m. As such, in
certain embodiments, the microfiber web of the second support layer
70 may include a pore size from at least about any of the
following: 100, 200, 300, 400, 500, and 1000 nm and/or at most
about 200, 100, 50, 40, 30, 20, 10 and 1 .mu.m (e.g., about 100
nm-1 .mu.m, about 500 nm-1 .mu.m, etc.).
It should be understood that the water purification device 10, as
described herein, may contain a heavy metal removal layer 20, a
support layer 30, and a biological species removal layer 40.
However, the water purification device 10 may additionally include,
alone or in any combination, the PFC removal layer 45, the
anti-fouling layer 50, the enhanced biological species removal
layer 60, or the second support layer 70.
Example embodiments therefore represent a water purification device
that may include a heavy metal removal layer configured to remove
heavy metal ions from contaminated water. The water purification
device may further include a biological species removal layer
configured to remove biological species from the contaminated water
and a support layer configured to provide support for the water
purification device.
In some embodiments, additional optional structures and/or features
may be included or the structures/features described above may be
modified or augmented. Each of the additional features, structures,
modifications, or augmentations may be practiced in combination
with the structures/features above and/or in combination with each
other. Thus, some, all or none of the additional features,
structures, modifications, or augmentations may be utilized in some
embodiments. Some example additional optional features, structures,
modifications, or augmentations are described below, and may
include, for example, that the support layer is disposed between
the heavy metal removal layer and the biological species removal
layer. Alternatively or additionally, the heavy metal removal layer
may include a nanofiber web having a functional group bonded
thereto, wherein the functional group is configured to attract and
bond heavy metal ions. In some cases, the functional group may be a
thiol functional group. In other example embodiments, the thiol
functional group may include thiol-ethanol. Alternatively or
additionally, the nanofiber web of the heavy metal removal layer
may include at least polyethylene terephthalate. Alternatively or
additionally, the biological species removal layer may include a
plurality of positively-charged nano-whiskers. In some cases, the
positively-charged nano-whiskers may be aluminum oxide hydroxide
nano-whiskers. In further example embodiments, the aluminum oxide
hydroxide nano-whiskers are in boehmite form. Alternatively or
additionally, the support layer may include a microfiber web. In
some cases, the microfiber web of the support layer may include
deep groove microfibers. In some cases, the deep groove microfibers
may be micron-sized deep groove microfibers. Alternatively or
additionally, the water purification device may further include an
anti-fouling layer configured to prevent clogging of the water
purification device. In some cases, the anti-fouling layer may be
located on a first end of the water purification device such that
the contaminated water flows first through the anti-fouling layer.
Alternatively or additionally, the anti-fouling layer may include a
nanofiber web with nanoparticles embedded therein, where the
nanoparticles are configured to prevent adhesion of particles from
the contaminated water onto the first end of the water purification
device. In some cases, the nanoparticles are chitosan
nanoparticles. Alternatively or additionally, the nanofiber web of
the anti-fouling layer may include at least polyvinyl alcohol.
Alternatively or additionally, the water purification device may
further include an enhanced biological species removal layer
configured to remove biological species not removed via the
biological species removal layer, where the biological species
removal layer may be positioned in the water purification device
such that the contaminated water flows first through the biological
species removal layer before flowing through the enhanced
biological species layer. Alternatively or additionally, the heavy
metal removal layer may be further configured to remove
perfluorinated compounds from the contaminated water. Alternatively
or additionally, the water purification device may further include
a perfluorinated compound removal layer configured to remove heavy
metal ions and perfluorinated compounds not removed via the heavy
metal removal layer, wherein the heavy metal removal layer is
positioned in the water purification device such that the
contaminated water flows first through the heavy metal removal
layer before flowing through the perfluorinated compound removal
layer.
Many modifications and other embodiments of the water purification
device set forth herein will come to mind to one skilled in the art
to which these inventions pertain having the benefit of the
teachings presented in the foregoing descriptions and the
associated drawings. Therefore, it is to be understood that the
water purification device is not to be limited to the specific
embodiments disclosed and that modifications and other embodiments
are intended to be included within the scope of the appended
claims. Moreover, although the foregoing descriptions and the
associated drawings describe exemplary embodiments in the context
of certain exemplary combinations of elements and/or functions, it
should be appreciated that different combinations of elements
and/or functions may be provided by alternative embodiments without
departing from the scope of the appended claims. In this regard,
for example, different combinations of elements and/or functions
than those explicitly described above are also contemplated as may
be set forth in some of the appended claims. In cases where
advantages, benefits or solutions to problems are described herein,
it should be appreciated that such advantages, benefits and/or
solutions may be applicable to some example embodiments, but not
necessarily all example embodiments. Thus, any advantages, benefits
or solutions described herein should not be thought of as being
critical, required or essential to all embodiments or to that which
is claimed herein. Although specific terms are employed herein,
they are used in a generic and descriptive sense only and not for
purposes of limitation.
* * * * *